15. Consider the surfaces S and H show below right; the boundary of S is the unit circle in the xy-plane, and H has no boundary. For each part, circle the best answer. F⚫n dA is: (a) For F = =(yz, xz + x, z), the integral negative zero positive (1 point) (b) The flux of curl F = (-x, y, 1) through H is: negative (zero) positive (1 point) (c) The integral (curlF) dS is: -2л ·元 0 π 2π (2 points) S (d) For G = (y, z, 2), the integral f G⚫n dA is: -2л - π 0 π 2π (2 points) H n